BDBK004-CH68.indd Page 765 12/17/07 10:14:10 PM epg /Volumes/ju108/BDBK004/BDBK004-Duggan%0/BDBK004indd/CH68 68 Enteral Nutrition Maria-Luisa Forchielli, MD, MPH, FACG Julie Bines, MD, FRACP The delivery of food via a tube directly into the enzymes and gastrointestinal hormones. Intesti- to development of normal intestinal fl ora and the gastrointestinal tract has been described since nal functional and structural changes occur intestinal immune system has been recognized.24 pre-Christian times. In ancient Egypt, and later in through local and systemic interaction of nutri- The interaction between specifi c bacteria and Greece, feeds were introduced into the rectum, ents and neuroendocrine peptides, cytokines, and toll-like receptors located on intestinal entero- and in the nineteenth century, rudimentary tubes hormones.10–12 The list of these mediators is con- cytes and lymphoid cell from as early as birth were used to infuse basic foods such as broths, stantly growing and includes gastrin; enteroglu- infl uences the development of physiologic intes- eggs, milk, and even alcohol into the esophagus cagon; peptide YY; interleukin 3, 11, or 15; tinal immune response.24 The provision of nutri- and stomach.1 Despite the increasing sophistica- epidermal growth factor; growth hormone; insu- ents via the intestine results in improved tion in other areas of medical care over the past lin-like growth factors I and II; glutathione; fi ber; utilization of digested and absorbed nutrients. century, treatment with enteral nutrition had been short-chain fatty acids; glutamine; triglycerides; Gut and liver work in synchronism utilizing and slow to develop. However, over the past two dietary nucleotides; and polyamines.10–12 Mono- eliminating nutrients. The actions of digestion decades, enteral nutrition therapy has undergone saccharides and fatty acids can infl uence the and absorption in the gut followed by a fi rst-pass a renaissance.2–7 Many patients who previously secretion of enteroglucagon and peptide YY and metabolism in the liver contribute to maintenance received parenteral nutrition are now successfully via these mediators effect mucosal growth and of physiologic metabolism. managed with enteral nutrition alone or in combi- decrease intestinal transit time.13 Carbohydrate, nation with parenteral nutrition.2,3,8 This has been protein, zinc, magnesium, potassium, or manga- COST made possible by the increasing range of options nese defi ciency can modify the effect of growth for gastrointestinal access, improved delivery hormone and insulin-like growth factor II.14–16 Although enteral nutrition therapy is more systems, and advances in enteral nutrition formu- Intraluminal nutrients assist in the mainte- costly than standard feeds, compared to paren- las. Home enteral nutrition therapy is now an nance of gut mucosal mass, including the gut- teral nutrition therapy, enteral nutrition is important adjunct to the management of infants associated lymphoid tissue (GALT). The GALT approximately two- to fourfold cheaper on an and children with chronic disease or feeding consists of the lamina propria, intraepithelial inpatient or out-patient basis.2,3,9,25–27 Based on problems.6 lymphocytes, immunoglobulin A (IgA), Peyer’s US Medicare charges, the annual cost of provid- patches, and mesenteric nodes and is responsible ing enteral nutrition per patient is approximately for processing intestinal antigens.17 During peri- PRINCIPLES OF ENTERAL NUTRITION US$9,605 � US$9,327 compared with ods of “bowel rest,” such as occur with intrave- US$55,193 � US$30,596 for parenteral solu- nous feeding and starvation, there is a reduction Enteral nutrition therapy has a number of advan- tions.4 In addition, the frequency and cost of in gut mass and the function of the GALT is sup- tages over parenteral nutrition in the management hospitalization is higher for patients supported pressed.17 This has been associated with a reduc- of patients requiring nutritional support. Enteral on parenteral nutrition therapy compared with tion in IgA secretion and increased gut nutrition aids in the preservation of gastrointesti- enteral nutrition therapy.4 permeability resulting in increased bacterial nal function by the provision of enteral nutrients adherence to the intestinal wall, cellular injury, and is easier, safer and less costly to administer. and bacterial penetration with adverse systemic MANAGEABILITY AND SAFETY However, despite these relative advantages, the host responses.17–19 In animal studies, an associa- delivery of safe and effective enteral nutrition tion between parenteral nutrition and bacterial Due to advances in technology of enteral feeding therapy may still present challenges for families translocation has been reported; however, these tubes and delivery systems, specialization of and caregivers in terms of time, technical exper- results have not been replicated in humans.20 Oral health professionals, and better education of par- tise, and cost.9 or enteral feeding may reduce the potential risk of ents and caregivers, the administration of enteral bacterial translocation, except when disturbances nutrition has been associated with improved clin- PRESERVATION OF in intestinal permeability are related to an under- ical outcome and safety profi les.28 Enteral nutri- GASTROINTESTINAL FUNCTION lying disease process (eg, short-bowel syndrome) tion therapy is easier and safer to administer than or the chemical composition of the enterally pro- is parenteral nutrition. Not only are the risks of Enteral nutrition mimics the normal gastrointesti- vided substance (eg, blue food dye).17,21–23 intravenous access avoided, but there is also a nal response following the ingestion of a meal, The gastrointestinal tract is a delicate ecosys- wider margin for error with most metabolic com- with the exception of the oral phase. The pres- tem with the balance determined and maintained plications. As a result, enteral nutrition therapy is ence of nutrients within the intestinal lumen pro- through the interplay between nutrients, bacteria, easier to administer in low-intensity hospitals and vides stimulation of gastrointestinal function and and the intestinal defense system (luminal, muco- patient care settings, including the home. How- helps to maintain the complex intraluminal envi- sal, and submucosal immune system). Intralumi- ever, compared with normal diet, tube feedings ronment via a number of key mechanisms. nal nutrients play an important role in the require extra time and effort to administer and Intraluminal nutrients stimulate gastrointesti- development and function of the gastrointestinal this additional care need may contribute to nal neuroendocrine function, effecting motility, ecosystem through the modulation of the resident increased burden and stress for families and care- and digestion through the secretion of digestive bacterial fl ora. The key contribution of prebiotics givers.9,29 Compliments of AbbottNutritionHealthInstitute.org With permission from Duggan C, et al. Nutrition in Pediatrics. 4th ed. Hamilton, Ontario, Canada: BC Decker Inc; 2008. BDBK004-CH68.indd Page 766 12/17/07 10:14:10 PM epg /Volumes/ju108/BDBK004/BDBK004-Duggan%0/BDBK004indd/CH68 766 PART VI / Approach to Nutritional Support INDICATIONS FOR necrotizing enterocolitis and toxic megacolon, ENTERAL NUTRITION Table 1 Indications for Pediatric Enteral Nutrition severe intractable vomiting or diarrhea, diffuse 1. Inability to ingest adequate nutrition orally peritonitis, and mechanical intestinal obstruc- Enteral nutrition should be considered for any i. Disorders of sucking and swallowing tion.7,34 Extreme care should be taken when patient with a functional gastrointestinal tract • Prematurity administering enteral nutrition in patients in who requires nutritional support. Enteral feeding • Neurological and neuromuscular disorders whom the gastrointestinal blood fl ow could be may be required if adequate oral nutrient intake (eg, cerebral palsy, dysphagia) compromised, such as during treatment with ii. Congenital abnormalities of the upper gastro- cannot be provided in children with growth fail- intestinal tract or airways hypothermia, low cardiac output, multiorgan fail- ure, weight faltering, or weight defi cit. This may • Tracheoesophageal fi stula ure, chronic occlusion, compression syndromes, be defi ned as a child with a weight or weight for iii. Tumors or infusions of specifi c drugs. However, in addi- height less than 5th percentile below the mean for • Oral cancer tion to a reduction of caloric defi cits, enteral sex and age and/or crossing of two growth curves • Head and neck cancer nutrition has been shown to protect the splanch- on the weight, height, or weight/height percentile iv. Trauma nic oxygen balance during intraoperative duode- charts, no weight gain or weight loss during the v. Critical illness 35 • Mechanical ventilation nal feedings in severely burned patients. last 2–3 months and/or triceps skin fold measure- vi. Severe gastroesophageal refl ux ments less than 5th percentile. Children with vii. Drug related ROUTES OF ADMINISTRATION severe neurological dysfunction may require pro- • Chemotherapy longed periods devoted to oral feeding. Tube vii. Severe food aversion During enteral nutrition therapy, nutrients are feeding can provide welcome respite for families viii. Severe depression directly delivered via a tube into the stomach, and caregivers who previously may have spent 2. Disorders of digestion or absorption i. Cystic fi brosis duodenum, or jejunum. The tube is inserted